Combustion apparatus



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`COMBUSTION APPARATUS Patented Oct. 15, 1935 UNITED STATES PATENT OFFICE COMBUSTION APPARATUS Hingham, Mass.

Application November 15, 1930, Serial No. 495,863

2 Claims. (Cl. 110-36) 'This invention relates to combustion apparatus for burning solid fuel.

One object of the invention is to provide a novel and improved construction of combustion apparatus which may be economically manufactured and nds particular use as automatic heating apparatus for Vthose uses requiring a comparatively small capacity, such for example as heating Yapparatus for heating domestic hot water supply, for heating garages, small greenhouses, and small dwelling houses.

With this object in view and such others as may hereinafter appear, the invention consists in the combustion apparatus and in the structures, arrangements', and combinations of parts hereinafter described and particularly defined in the claims at the end of this specication.

In the drawings illustrating the different features of the invention, Fig. 1 is a vertical sectional view of Aan automatic heating apparatus for heating a domestic hot water supply; Fig. 2 is a sectional View taken on the line 2--2 of Fig. 1 Fig. 3 is a detail in side elevation illustrating the grate operating mechanism; and Fig. 4 a detail to be referred to.

In general the present invention contemplates a novel construction of combustion apparatus in which the combustion is caused to take place'upon a mechanically moved grate within the repot, and in which provision is made for supplying air, preferably under pressure, through the grate to maintain the combustion. The solid fuel is maintained in an ample supply for operation of the apparatus for a substantial length 35 of time, as for example a week, within a reservoir located above the grate, and provision is made for permitting the fuel to automatically feed by gravity downwardly onto the grate, thus obtaining the benefits of efiicient combustion on 40 an overfeed principle. The operation of the grate and the air supply are preferably controlled in denite relation to maintain the most eiiicient combustion. Provision is also preferably made for the disposition of ash in a novel manner, thus enabling the apparatus to operate automatically for a substantial period of time, as for example a week.

As above indicated, the present invention aims to provide a novel construction of combustion 50 apparatus for burning solid fuel such as the difyferent grades of bituminous and anthracite coal and coke, and which is designed to supply the need of a small heating unit forheating domestic water supply, garages, small greenhouses, and

even small dwellings, in an automatic manner. 5

` ing apparatus now upon the market and which is suitable for the purposes and uses referred to, and which may operate to efficiently burn the more inexpensive grades of fuel with accompanying economies in the heating costs. The need of such an apparatus is particularly apparent in certain outlying districts where gas is not available, although the apparatus may also be used with advantage wherever a relatively small heating capacity is required.

Referring now to the drawings, which as above stated illustrate the preferred embodiment of the invention, theinvention is as above stated therein illustrated as embodied in apparatus for heating a supply of domestic hot Water and contemplates a combustion chamber I0 formed within the body of the furnace, the lower portion I2 of the walls of which is preferably tapered as shown, and surrounds a conical lgrate I3 having a plurality of air passages I4 therein for the passage of air upwardly through a bed of fuel maintained upon the grate. The periphery of the base of the conical grate I3 is spaced a short distance from the surrounding lower portion I2 of 35 the walls of the combustion chamber to permit the passage of ash therebetween as the conical grate is rotated. Ribs I8, I9 are provided upon the surface of the conical grate and upon the surrounding dead plate for assisting in breaking up the ash as the grate is rotated. The conical grate I3 is hollow and the interior thereof is preferably connected by an air pipe 20 to a blower or fan 2l driven by a motor 22, as illustratedin Fig. 2. and the flow of air through the air'pipe 20 is controlled by a damper 24 herein shown as operatively connected to the mechanism for moving the grate to the end that the proportion of air to the fuel fed and the rate of combustion may be properly maintained. The

conical grate I3 is herein shown as supported upon bearings 28 Within a raceway 29 formed in a transverse supporting member 30, and provision is made for rotating the grate through the cooperation of a bevel gear 32 with a ring gear 34 mounted upon the bottom of the conical grate. 'Ihe bevel gear 32 is mounted upon the end of a drive shaft 36 journalled in bearings 38 supported in the casting forming the support or bottom portion of the combustion apparatus as illustrated in Fig. 1. The shaft 36 has axed to its outer end a ratchet 40 with which a Ypawl 42 cooperates to advance the ratchet and consequently to effect the rotation of the conical grate when the pawl is advanced during its oscillation. The pawl 42 is Vcarried upon the top of a pawl arm 44 connected to an arm 46, the latter being connected by a link 48 to a crank' 5ll.v The crank 5U is arranged to be'rrevolvedfrom the motor 22 through the mediurnof afreduction gear mechanism which may comprise any usual or preferred form now upon the market. The manner in which these partsV cooperate is clearly illustrated in Fig. 2. c

Provision is made for controlling the effective throw of the pawl 42 to control the extent of grate movement, and `as Yherein-shown a shield member 52 pivoted upon the shaft 36 is arranged to be moved relative to the pawl so as to slide under a pin 54 projecting from the pawl to maintain Ytliejnose of the pawl disengaged from `the teeth of the ratchet for the desired portion of the normal stroke of the pawl, to thereby prevent it from picking up any desired number of teeth. 'Ihe pivoted shield 52 is preferably connected to a control link running from va thermostat or from a manual controle A connection is also preferably made between ythe shield and the air damper 24, thus controlling the supply of air to the grate n accordance with the extent of grate movement so that most eilicient combustion may be secured irrespective of the rate. 1 In order to supply the fuel to the conical grate I3, I provide a fuel reservoir 60 located above the grate in a position from which the fuel may automatically flow onto thegrate by gravity. rI'he flow of the fuel is preferablyV controlled by the bed of fuel on the grate, so that the supply may be automatic as long as fuel remains in the The reservoir 60Y is preferably made reservoir. of a size su'icient to provide fuel for a substantial period of time, as for example for a week, during which the feeding of the fuel onto the grate is carried on in an automatic manner. As herein shown the fuel reservoir 60 is cast integrally with the combustion chamber, with the bottom walls 62 of the reservoir inclined at the correct angle to insure free flow of the fuel to the discharge orifice 64.v The latter comprises preferably a pipe section located over the apex of the conical grate I3 and spaced therefrom a distance "such that a conical bed of fuel such as is indicated by the dotted lines 68 is maintained at all times upon the grate. During the combustion the grate is slowly moved and the ash is discharged over the base of the grate falling down through the` discharge opening formed between the periphery of the grate-and the lower portion of the walls of the combustion chamber where the ash is collected in a removable ash receptacle 'I0 located-below the grateasillustrated in Fig. 1. Thefront end of the lower portion of the apparatus may be openin order to permit the ash receptaclefto Ybe readily withdrawn from its illustrated position. When in its operative position,

such as is shown in Fig. 1, the lip of the ash receptacle preferably forms a dust and air-tight joint with the annular portion 'I4 of the furnace shell to maintain an air and dust-tight chamber below the grate. The removable ash receptacle is an important part of the present combustion apparatus in that it avoids the handling of the ashes other than in containers, thus facilitating the work of removing the ashes and avoiding al1 bulk handling thereof with its dirt and inconvenience. Therfuel reservoir 60 1s provided with a cover member 6I for preventing the escape of gases from the combustion chamber.

In the operation of the present apparatus, as i combustion proceeds, the conical fuel bed is main- `tained at the proper and most desirable thickness by the automatic flow of the fuel from the fuel 'reservoir andthe conical shape of the grate. In Aoperation when the grate is moved and combus- Y tion proceedsgthe fuel bed gradually shrinks, thus permitting the flow of additional fuel from the supply reservoir. In addition the motion of the grate controls the rate of removal of the ash, thus tending to diminish the volume of the fuel bed which is, however, maintained at its correct volunie by the illow of additional fuel.

While different forms of a power operated grate member may be utilized in the present unit, if found advantageous, I prefer to utilize a conical grate arranged as illustrated having the air passages I4 for providing the primary air through the `fuel bed, and further having provision for sup plying the necessary secondary air through an opening 'I6 in the apex of the conical grate, thus enabling most efficient combustion of the fuel to be obtained.

The present combustion apparatus is particularly adapted for use in heating water for those heating purposes requiring moderate or relatively small treating capacities, such lfor example as the heating of domestic water supply, and for some purposes the grate movement and the air supply may, in the manner above described, be controlled manually or by any usual or preferred form of thermostatic control, so that as long as a supply 'of fuel remains in the fuel reservoir the operation of the combustion unit may be rendered automatic.

While the preferred embodiment of the inventionhas been herein illustratedand described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:- Y

Y 1. In a heating apparatus for domestic use ln burning solid fuel, in combination, a combustion chamber, a grate rotatably mounted therein, fuel feeding means responsive to and controlled by the volume4 of the fuel bed, said fuelfeeding means and grate cooperating to maintain a relatively thin fuel bed on the grate, a motor and connections between the motor and the grate for intermittently rotating the grate during the combustion of the fuel to thereby effect the continuous elimination of excess ash and to maintain the thin fuel bed in an incandescent condition during combustion, air supply means and means for effecting the operation of the air supply means and the rotation of the grate in predetermined relation.

2. In a heating apparatus for domestic use in burning solid fuel, in combination, a combustion chambena grate rotatably mounted therein, fuel feeding means responsive to and controlled by the volume of the fuel bed, said fuel feeding means and grate cooperating to maintain a. relatively thin fuel bed on the grate, a motor and connections between the motor and the grate for intermittently rotating the grate during the combustion of the fuel to thereby eiect the continuous elimination ofI excess ash and to maintain the thin fuel bed in an incandescent condition during combustion, air supply means, means for eecting the operation of the air supply means and the grate rotating means in predetermined relation and means for adjustably varying the rate of operation of one of said means.

LAWRENCE W. CORBETI'. 

